Collagen sponge (CS), highly crosslinked, with large pore size and high resilience, is readidy permeated by cells, and cell products after inplantation in tissue. It has controllable rate of resorption and no detectable antigenicity. Because of these and other unique characteristics, we propose to study the biomedical aspects of using CS as a burn dressing, temporary substitute for bone and articular cartilage and as a surgical tampon. Animal models of clean and septic third degree burns in rabbits and pigs, defects of bone and articular cartilage in dogs and pigs will be induced and collagen sponge tested in comparison with other competitive biomaterials and in appropriate application. In addition, CS will be combined with hydroxyapatite, Ca3(PO4)2 or Hydron to achieve more rigid structure for bone remodelling. To achieve the fastest tissue replacement, CS will be seeded with osteoblasts or chondrocytes also. A complex of surgical, biological, morphological, bioengineering and biochemical methods will be used to evaluate the dynamics of wound healing, oste- and chondrogenesis. Several basic problems involved in using CS will be tested, such as the role of pore size, resilience, rate of resorption on cell ingrowth, etc. The final goal is to find the real value of CS as biomaterial in some crucial medical applications.